This invention relates to packaging of food and agricultural products.
Polymeric film materials such as cellophane, polyolefins, polyamides, vinyl-series polymers, et cetera are widely used to package food and agricultural products. For better reliability and technological adaptability, the film materials are made in a multi-layer form so that the layers are joined through the use of adhesive compositions. Use is also made of previously stretched films which shrink following packaging as in the case of heat-shrinking multi-layer films. A disadvantage of such packaging is the large labor consumption during the manufacture and the expenditure of materials.
To impart spectral properties to packaging materials, they may be subjected to diffusion stabilization in softening solutions. For example, fungicides such as imidazole or triazole are introduced into one layer of the polymeric film; tile layers contacting the products in these multilayer materials, however, are typically made of modified polyolefin. These materials are expensive and poorly adapted for technological processes and, in some cases, do not prevent the contained food products from spoiling.
There is one material which has an inner layer of film comprising 70-90 parts of high density polyethylene and 30-10 parts of monomer having a fusion index 2.5-10 times as high as that of polyethylene. The disadvantage of the prior art subject matter consists in that selection of the packaging material components is significantly limited by toxicity of the monomers, and only very little of them -are allowed to contact the food products due to medical and/or sanitary criteria.